Legionnaires’ outbreak in Upper East Side linked to cooling towers, city orders disinfection

Legionnaires’ outbreak grows in Upper East Side as city targets cooling towers

An outbreak of Legionnaires’ disease has sickened 46 people on Manhattan’s Upper East Side, New York City officials said this week, prompting an aggressive campaign to test and disinfect suspected building cooling towers.

City health authorities reported the cluster after linking infections to contaminated water cooling towers; the announcement came as 22 of the ill sought hospital care, with several patients treated in intensive care, health officials said on Wednesday evening.

Legionnaires’ is a serious pneumonia caused by Legionella bacteria that thrive in warm water and spread when people inhale contaminated mist from cooling systems, Dr Wafaa El-Sadr of Columbia University’s Mailman School of Public Health explained.

The health department said it is testing roughly 160 cooling towers across the affected area and will require immediate cleaning and disinfection of any tower that tests positive rather than waiting for confirmatory results.

Some building owners have already completed the mandated cleanings, while others are beginning the process, officials said, and the city stated it would continue broad testing of water cooling systems in the neighbourhood.

At a community town hall held in an Upper East Side church, Health Commissioner Alister Martin described early identification of cases as positive, saying the department was not waiting to act on the 160 towers under review.

City Council speaker Julie Menin, however, told attendees she remained concerned the Department of Health and Mental Hygiene had not required proactive disinfection of all cooling towers within the investigation area and raised the issue in a letter to Commissioner Martin.

Residents at the meeting, including Justine Kirby, said they are taking personal precautions such as wearing N95 masks outdoors and keeping windows closed while the contamination is addressed, though the health department did not specify a community masking recommendation.

Dr El-Sadr noted that masking and closing windows could help people living near the outbreak epicentre, and warned that warming temperatures related to climate change can worsen the conditions that favour Legionella growth.

City data indicate the Upper East Side hosts a large number of cooling towers—more than three times the number tested during a 2025 Harlem outbreak that sickened 114 people and caused seven deaths—underscoring the scale of the current inspection and remediation effort.